1. Field of the Invention
The present invention relates to a rolling guide apparatus having rollers which under go rolling movement and are interposed between a raceway shaft and a movable member, as well as to a roller connecting member for retaining the rollers in a rotatable and slidable manner.
2. Description of the Related Art
A rolling guide apparatus comprises a track rail; a moving block which is movably provided along the track rail via a plurality of rolling elements; and a plurality of rollers to be interposed between the track rail and the moving block. FIG. 1 shows a rolling guide apparatus having rollers incorporated therein. When a moving block 101 has moved with respect to a track rail 104, rollers 100 located in a load area defined between two roller raceway surfaces 102 undergo rolling movement, thereby pushing rollers 100 located in a non-load area B. Then, the rollers 100 located in the non-load area B are pushed into a load area A on the remaining side. Thus, the rollers 100 circulate through a roller circulation path defined along the moving block 101.
A ball is the form of a sphere, and contains an indefinite number of rotation axes. Therefore, the ball can move in any direction as circumstances demand. Since the rollers 100 are cylindrical, each roller 100 has only one axis of rotation, and hence the moving direction of the roller 100 is limited to solely one direction. The rotation axis of the roller and the moving direction of the same must maintain a right angle. In relation to a linear motion guide apparatus using the rollers 100, if the roller raceway surface 102 of the moving block 101 has come out of parallel with the roller raceway surface 102 of the track rail 104 or if an offset load has acted on the moving block 101, there may arise a change of a rotation axis 105 of the roller 100 and the moving direction of the same failing to form a right angle, as shown in FIG. 2. Such a phenomenon in which the rollers 100 are inclined with respect to the normal axis of rotation is called “skew.” In the case of a linear motion guide apparatus of all-roller type in which a plurality of only rollers 100 are incorporated into the roller circulation path, the end faces of the respective rollers 100 located in the direction of the rotation axis come into contact with a flange 103 formed on the moving block 101, thereby preventing occurrence of skewing of the rollers 100.
If load acts on the linear motion, rolling elements, the moving block 101, or the track rail 104 will be resiliently deformed. The extent to which the rolling elements, the moving block 10, or the track rail 104 resists deformation is called the rigidity of the linear motion guide apparatus. A linear motion guide apparatus in which balls are incorporated as the rollers 100 generally has greater rigidity than does the linear motion guide apparatus in which balls are incorporated as rolling elements. The rigidity of the linear motion guide apparatus having rollers incorporated therein is determined by the number of rollers 100 and the axial length of the same. The greater the number of rollers 100 and the longer their axial length, the greater the rigidity of the linear motion guide apparatus. In other words, incorporation of a large number of elongated rollers into the linear motion guide apparatus is effective for increasing the rigidity of the same.
When elongated rollers are used for enhancing rigidity, there cannot be ensured a large contact area between the end face of the roller 100 and the flange 103 with respect to the length of the roller 100 in a rotating direction there of. Hence, skew is apt to arise in the rollers 100. Consequently, there may arise problems; that is, a phenomenon of rollers failing to rotate (i.e., a locking phenomenon), a heating phenomenon, or a phenomenon of a table oscillating for reasons of vibration which arises when the rollers are located in a load area (i.e., a waving phenomenon).